There are several exclusive figures on the run for different types of events.
Primaris Lieutenant Amulius (below) is an events exclusive only model. Things like Adepticon.
There's a Primaris Space Marine Captain and Nighthaunt Hero (Darrakar) which are only available at Store Anniversaries/Birthdays:-
And finally, there's the New Store Opening Exclusives, which involves two stormcast heros, a Terminator Chaplain, and a Terminator Captain.